How to Do Hack Squats to Build Serious Lower-Body Strength

Love 'em or hate 'em, squats are one of the most famous leg exercises out there for a reason: They improve strength and stability in your quads and glutes, and they help you practice a movement pattern you perform on the daily, such as when you rise up off the couch or drop down low to pet your dog. And the hack squat — a popular variation you perform on a machine — is no exception.

But how does the hack squat stack up against its machine-free counterparts? Here, fitness experts share the biggest benefits the exercise has to offer and break down how to do a hack squat to score those perks. Trust, you don't want to skip out on this leg-strengthening move.

How to Do a Hack Squat

The hack squat machine looks kind of like a reverse leg press machine, explains Pete McCall, M.S., C.S.C.S., an ACE-certified personal trainer and the host of the All About Fitness Podcast. To use a leg press machine, you sit on a fixed seat and push your feet against a weighted, moving platform that's above you. To use the hack squat machine, however, you'll stand on a fixed platform (facing away from the machine) beneath shoulder pads, then lower your butt down to the platform as if you were doing a traditional squat. Since the weight is equally distributed across your shoulders and you're able to heavily load the machine, the hack squat functions much like a barbell back squat, says Lauren Saint-Louis, an NSCF-certified strength coach and Tier X Coach at Equinox, who demonstrates the move below.

A. Stand in a hack squat machine with feet shoulder-width apart and positioned in the top half of the platform, shoulders and hips resting against the back rest, and hands holding onto the handle bars.

B. On an inhale, bend knees to lower until thighs are parallel or just below parallel with floor, keeping shoulders and hips pressed against the back rest.

C. On an exhale, press through feet to straighten legs and return to standing.

The Key Hack Squat Benefits

Although the hack squat seems pretty darn basic, the lower-body move offers plenty of perks for your lower body and joints.

Isolates the Quads

One of the biggest perks of performing hack squats: building strong and powerful quad muscles (the muscles at the front of your thighs), says Saint-Louis. "They isolate the quad muscles for optimal growth," adds McCall. ICYDK, the quad muscles play a role in moving and stabilizing the knee cap, flexing the hip, and regulating your gait,so it's important to keep them strong and healthy, according to the Cleveland Clinic. Plus, hack squats can help bodybuilders and figure athletes achieve the particularly Herculean-looking quads they need to succeed in their sport.

Provides Stability

Unlike squats performed with free weights — which require a lot of core stability on your part—hack squats keep your upper back and hips in a stable position, explains McCall. "The hack squat can isolate the position of your body, so it's much more stable," adds Saint-Louis. "So you can load it really heavy [without] having to focus on staying upright."

And that added stability is also what makes the hack squat a less-risky alternative to barbell back squats, especially if you're new to the weight room, according to the experts. "Hack squats are likely safer than barbell squats since you don't have to balance free weights and can't fall backward or forward," says Wilson.

Doesn't Require as Much Ankle Mobility

Typically, the foot platform is angled away from you so that your toes are slightly furtherfrom your body than your heels, positioning your body as if you are doing traditional squats with weight plates under your heels. "This [angle] reduces your need to have lots of ankle mobility in order to correctly perform the movement," adds Jacob Wilson, Ph.D., C.S.C.S.*D., the CEO of the Applied Science & Performance Institute and a member of The Vitamin Shoppe's Wellness Council. Translation: The hack squat can be useful for folks who have limited ankle mobility and don't feel totally comfortable performing other heavily loaded squat variations, says Saint-Louis.

Hack Squat Muscles Worked

As previously pointed out, your quads do most of the work during hack squats, though your glutes also come into play, says Saint-Louis. Your hamstrings and core are involved, but their role is minor, she adds. Remember: The machine provides plenty of stability, so your core doesn't need to work as hard to keep you upright. Since your hips are in a fixed position, your knees do most of the work, and your hamstrings aren't called on to extend the hip joint. But be warned:All that extra emphasis on your knees isn't necessarily a good thing. "If the hips and knees don't move in sync, you could risk knee injuries from overuse or over-flexing the joint," explains McCall.

Due to the extra stability for the hips, hack squats involve a different movement pattern than traditional squats, during which the hips move back and the knees simultaneously bend, says McCall. Consequently, other squat variations distribute the work more evenly among your quads, hamstrings, glutes, and lower back.

Hack Squat Exercise Variations

Since the hack squat machine puts your body in a fixed, stable position, it's pretty tough to modify and progress the exercise, says Saint-Louis. However, there is one hack squat variation you can use to spice up your workout. And if you don't have access to a hack squat machine, you can replicate the move using another common piece of gym equipment.

Variation: Face the Machine

If you're in the mood to amp up the challenge on your glutes, try a reverse hack squat, in which you stand facing the machine instead of away from it. In this position, your hips aren't locked into a specific motion path, since your shoulders and feet are the only points of contact with the machine. "This switches the emphasis from your quads to your hamstrings and glutes," says Wilson. Because most hack squat machines have angled platforms, this may be a bit trickier to pull off if you have tight ankles; you'll need decent ankle mobility to squat with your feet already flexed toward the floor.

Variation: Use a Smith Machine

Despite the exercise's perks, not all gyms have a hack squat machine on hand. In that case, you can replicate the hack squat on the Smith machine, says Saint-Louis. Instead of standing directly underneath the bar, you'll position your feet one step in front of the bar, then lean back slightly, resting the bar across your upper back. This trick will work your quads in a similar way as the hack squat, though your hips will move freely.

Common Hack Squat Mistakes

For the most part, your hack squat form will be the same as a traditional squat, but you will want to tweak your foot placement on the hack squat machineslightly. "Make sure your feet are a little bit further [up on the platform] so when you squat, your knees and hips are at a proper 90-degree angle and your knees stay stacked over your heels," says Saint-Louis. If your feet are too close to your body, your knees may jut out past your toes while you squat, placing even more stress on your knee joints.

And don't forget to drop as low into your squat as possible, working through your entire range of motion, says Saint-Louis. "If there's any time to squat deep, the best time would be on the hack squat machine because you have so many controlled factors," she explains. In other words, you don't have to worry about falling over or getting stuck in your squat with a heavy barbell if you were to drop too low to return to standing.

How to Add Hack Squats to Your Routine

Before you incorporate hack squats into your workout program, you'll first want to master the standard bodyweight squat and a front squat with a dumbbell or kettlebell, which ensures you'll have the proper movement pattern down pat, says Saint-Louis. If you're dealing with lower back issues or have any existing injuries, you should chat with your doctor first to confirm you're safe to squat with heavy loads, she says.

Once you get the all-clear, add the hack squat to the beginning of your strength workouts, which ensures you're not too fatigued to lift heavy, recommendsSaint-Louis. Aim to do four sets of about 12 reps or, if you want to put your muscles to the test, try pyramid sets. Start with a set of 20 reps at a light weight, then increase the load and do 15 reps, and continue the process for another two to three sets, suggests Saint-Louis. If you want to get the most bang for your buck on the hack squat machine, consider incorporating both typical hack squats and reverse hack squats into your routine so you give your hamstrings and glutes a little love too.

Just know that hack squats "don't necessarily improve the function of your hips and knees working together," says McCall. "Fixed-path machines aren't necessarily bad, but sometimes they restrict normal or optimal joint function—and this is one of those cases." (Experts generally agree that most workout machines can be risky or ineffective for the same reason.) Translation: Your body reaps a more well-rounded benefit from other, unrestricted types of squats, like bodyweight squats, goblet squats, or barbell squats.

Want to give your quads a little extra oomph? Try doing your usual squats (whether that's with a barbell or dumbbells or just your bodyweight) with 10-pound weight plates beneath your heels to mimic the hack squat position. But if hack squats get you seriously excited for leg day, go on ahead and incorporate them into your regularly scheduled programming.